Brachet P, Dicou E
Exp Cell Res. 1984 Jan;150(1):234-41. doi: 10.1016/0014-4827(84)90718-3.
Two mouse cell lines, 3T3 and L, reported to secrete an NGF-like activity in the culture medium were co-cultured with the pheochromocytoma cell line PC12 which responds to NGF in vitro. In these co-cultures mitomycin-treated L or 3T3 cells were employed at low cell density (1 000 cells/cm2). L cells, but not 3T3, promoted efficiently neurite outgrowth of PC12. The response of the PC12 cells was blocked by an antiserum to male mouse submaxillary gland beta NGF. The NGF secreted by the L cells and immunoprecipitated by this antiserum co-migrated with the submaxillary gland beta NGF monomer in SDS-polyacrylamide gels. Surprisingly the neurite-promoting activity of media conditioned by L or by L-PC12 co-cultures was at most one-tenth of that expected on the basis of the response of PC12 cells in the co-cultures. This was not due to proteolytic degradation of the NGF-like factor or to losses by manipulation of the media. It seems therefore that co-cultures provide conditions which enhance the effect of the factor. Possible mechanisms responsible for this effect are discussed.
据报道，两种小鼠细胞系3T3和L能在培养基中分泌一种类神经生长因子（NGF）活性，将它们与在体外对NGF有反应的嗜铬细胞瘤细胞系PC12进行共培养。在这些共培养实验中，用丝裂霉素处理过的L或3T3细胞以低细胞密度（1000个细胞/cm²）使用。L细胞能有效地促进PC12细胞的神经突生长，而3T3细胞则不能。PC12细胞的这种反应被抗雄性小鼠颌下腺β-NGF抗血清所阻断。L细胞分泌的并被该抗血清免疫沉淀的NGF在SDS-聚丙烯酰胺凝胶中与颌下腺β-NGF单体共迁移。令人惊讶的是，L细胞或L与PC12共培养条件下的培养基的促神经突生长活性最多只有基于共培养中PC12细胞反应所预期活性的十分之一。这不是由于类NGF因子的蛋白水解降解或培养基操作导致的损失。因此，似乎共培养提供了增强该因子作用的条件。文中讨论了造成这种效应的可能机制。
